As computing products continue to drop in price while increasing in power, printing technology is driven by the need to reduce prices while improving printer resolution. One technology under development is acoustic ink printing (AIP). AIP printing systems use focused acoustic energy to eject droplets of a fluid onto a recording medium. The fluid is typically ink, although in specialized applications, the fluid may be a molten solder, a hot melt wax, a color filter material, a resist, and various other chemical and biological compounds.
In AIP systems, a print head ejects and deposits droplets on a recording medium to form an image. Tight control of droplet size and droplet distribution is important to obtain high resolution accurate images. Variations in droplet size and deviations in droplet placement degrade the resolution of images output by the AIP system.
A typical print head, such as an AIP print head, includes a number of droplet sources. In an AIP system for printing, these droplet sources are often wells containing ink. Acoustic energy generated by a transducer is directed to cause ejection of droplets of ink from the well. A variety of manufacturing techniques, typically semiconductor processing techniques, may be used to fabricate the transducer, the circuitry driving the transducers, and the wells. During the manufacturing process, slight variations in manufacturing parameters result in slight differences in each transducer and/or well on a print head. Transducer or well differences result in each droplet source outputting a slightly different droplet size. The different droplet sizes from different droplet sources on the same print head reduces accuracy and uniformity of a printed image.
The placement of droplet sources across a printhead also causes droplet size variations. In some embodiments of a printhead, a small number or even a single radio frequency (RF) source is used to drive multiple droplet sources distributed across a printhead. The transducers closest to the RF source receive more energy resulting in larger droplets being produced compared to transducers on the same print head positioned further away from the RF source. The difference in RF energy received by droplet sources on the same print head results in droplet size variations which reduce the accuracy and uniformity of outputted printed images.